This invention relates to electrosurgery and, in particular, to electrosurgical instruments and methods of making and using them.
Heretofore, the active electrodes used in electrosurgical instruments have for the most part been made of steel, brass or stainless steel. Such electrodes have certain drawbacks. Thus, living tissue tends to adhere to these electrodes when implementing a surgical procedure such as cutting, coagulation, etc. This results in the tearing away of the tissue which can cause dangerous complications in some operations. Further, these electrodes tend to foul with the burned, adhered tissue. Thus, frequent cleaning is necessary.
Another problem associated with clogging or fouling of electrodes of the above type tends to occur with bipolar or sesquipolar devices. Refer to the above mentioned, co-pending patent application for a description of sesquipolar devices. Generally, in a sesquipolar device, arcing ideally occurs only at the active electrode where both the active and return electrodes are in the surgical site. In a bipolar device, if one electrode fouls more than the other, the clogged electrode will tend to arc preferentially thereby preventing the desired bipolar mode of operation where equal flesh interaction preferably occurs at the two electrodes. If the return electrode of a sesquipolar device clogs, there will be a tendency for arcing to occur at the return electrode. This is also undesirable since in a sesquipolar device arcing should occur only at the active electrode, as stated above.
Another problem associated with the use of electrodes of the above type is the tendency of such electrodes, when operated in the coagulation mode, to effect undesired, massive cutting of the tissue. Further, so-called "stimulation" currents tend to be associated with the use of electrodes of the above type. That is, when using such electrodes there is an undesirable tendency for nerves to be stimulated by currents of certain frequencies. Also, the amount of power required to use such electrodes tends to be high.